Oxidation kinetics and high temperature in-situ observation of the oxidation behaviour of NbSi_2 at 1023 K

Pest oxidation has been known for a long time in refractory transition-metal disilicides such as NbSi2 and MoSi2[1―4]. However, the origin of pesting reaction of these materials is still under debate. Although the pesting phenomenon in NbSi2 has been reported in several works[5―7], a direct study of the mechanism is scarce at the moment. Compared to NbSi2, pesting in MoSi2 has received relatively extensive attention. Mckamey et al.[8] showed fragmentation near 773K occurred easily in as…     

Bubble size measurement in three-phase system using photograph technology

A special experiment setup was designed to observe the interaction between bubbles and particle in flotation cell and to analyze the bubble characteristics such as bubble size, distribution and bubble-loading efficiency. Bubbles in water-gas system and three-phase system were measured. The results indicate that with the current setup the bubbles as small as 10μm can be easily distinguished. The average size of the bubbles generated under the given conditions in two-phase system is 410μm at frother concentration of 0. 004%, which is in good correspondence with the results of other works. The effect of frother on bubble size was probed. Increasing frother concentration from 0 to 0. 004% causes a reduction of bubble size from 700 to 400μm. The bubble loading efficiency was reported. The result indicates that the fine particle is more easily entrapped than the coarse particle. Some factors, which have effect on measurement accuracy were discussed. The aeration speed has a significant effect on the accuracy of results, if it surpasses 30 mL/s, and the image becomes unclear due to the entrapment of fine particle. Another factor, which can affect observing results, is the sampling position. At a wrong sampling position, the images become unclear.     

Psychology and Phenomenology: A Clarification.

Controversies are rampant in contemporary psychology concerning the appropriate method for observing consciousness and the role inner experience should play in psychological theorizing. These conflicting orientations reflect, in part, methodological differences between natural science and human science interpretations of psychology. Humanistic psychology and philosophical phenomenology both employ a human science approach to psychology that seeks to explain behavior in terms of a person's subjective existence. Maslow's and Heidegger's formulations are both fulfillment theories in that they specify moral values that suggest how life ought to be lived. Natural science methodology rejects the possibility that moral imperatives can be validated, whereas human science methodology allows phenomenological convictions to justify recommendations about a fulfilled life and a good society. The social role of psychology is analyzed within the framework of phenomenological convictions and scientific truth. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Influence diagnostics in regression with complex designs through conditional bias

One of the areas of Statistics in which the influence analysis has been widely studied is the multiple linear regression model. Nevertheless, the influence diagnostics proposed in this context cannot be applied to regression in complex survey, under randomized inference, since the i.i.d. case does not incorporate any probability weighting or population structure, such as clustering, stratification or measures of size into the analysis. In this paper we introduce some influence diagnostics in regression in complex survey. They are built on the conditional bias concept (Moreno-Rebollo et al., 1999). We emphasize the similarities and differences of the proposed measures with respect to the existing ones for the i.i.d. case. Research partly supported by the Spanish MCYT grant BFM2001-3844 and Spanish MEC grant MTM2004-0111433.     

基于矢量观测确定飞行器姿态的算法综述

随着无陀螺飞行器的出现，关于矢量定姿算法的研究已引起重视。这方面的理论基础比较薄弱，有待解决的问题还很多，为给今后的研究工作提供有用的参考，按照确定性算法与状态估计法的分类原则，介绍近几十年来国外研究者在矢量定姿算法研究方面所取得的主要研究成果，阐述典型算法的基本思想及其发展状况，并进行比较分析。结合航天科技发展现状及趋势，特别指出了无陀螺矢量定姿法研究的重要现实意义：不仅为促进小型（无陀螺）飞行器的发展奠定了理论基础，而且为延长载有陀螺飞行器的寿命提供一个新的解决思路。     

基于矢量观测确定卫星轨道姿态:欧拉角估计器

针对“矢量观测+陀螺”这种典型的三轴稳定卫星姿态确定系统配置模式,采用欧拉角作为姿态参数,应用扩展卡尔曼滤波技术综合处理姿态测量信息,给出了具有良好滤波性能的轨道姿态估计算法.在算法的设计过程中,针对单矢量观测情况,通过改进协方差修正算法加快了状态估值的收敛速度;针对多矢量观测情况,把 QUEST 法作为矢量观测数据压缩技术有效地结合进姿态估计器中,使得在多矢量观测情况下的滤波修正算法得到了简化.     

从空间对地观测到预测地球未来的变化(一)-NASA地球科学事业(ESE)战略计划述评

分析介绍了NASA的ESE战略计划,该计划以提高人类对地球系统的科学认识、改进对天气、气候和自然灾害的预测和预报为目的,通过观测、模拟等手段认识控制地球系统变化的过程,回答一系列地球系统科学问题;计划制定了未来十年NASA的科学、应用和技术目标,针对不同的科学问题确定了相应的卫星任务并且展望了预期成果。最后对ESE战略计划的若干特点进行了概括和分析。     

测量归心改正模型的完善

针对目前归心改正计算模型存在的问题，提出了用于归心改正计算的通用严密的数学模型．用该模型进行计算，可保证野外观测量在数学化算过程中不损失精度．     

基于直接转矩控制的高性能磁链观测与速度观测

提出了一种高性能的定子磁链和转子磁链的观测方法，并在转子磁链的基础上估算出电机转速，最后将结合磁链观测的速度估计器应用到无速度传感器直接转矩控制系统中。仿真和实验结果表明，这种观测方法能够提高速度的观测精度，增强系统的鲁棒性，并使直接转矩控制系统的低速性能得到较大提高。     

柴油机喷雾特性的传统及现代测试方法

介绍了近现代内燃机工作者为了研究柴油机喷雾特性所应用和研究开发的一系列测试柴油机喷雾场的方法及其工作原理，并比较了各种方法的优越性及局限性．最后提出了一个研究出一种能实现瞬态喷雾全场雾滴尺寸及速度同时测量的在线实时测量新技术必要性的观点。